Laser tube for a laser generator

ABSTRACT

A laser tube for a laser generator used in a laser machining tool is formed by a plurality of disks laminated together to form an integral unit. The disks have a main hole for the passage of laser gas and at least one sub-hole for a sub-flow of laser gas. The sub-hole of each disk is connected with the respective main hole of the disk by a gas injection channel through which laser gas is injected into the main hole at a plurality of longitudinal positions in the laser tube to provide a homogeneous laser gas velocity distribution in the laser tube.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a laser generator used in a laserprocess machine, and in particular to a laser tube which provides ahomogeneous laser gas velocity distribution in the laser tube.

2. Description of the Related Art

Generally, the types of laser generators commonly used in a laserprocess machine are the high speed axial, biaxial transverse, andtriaxial transverse types.

In particular, the high speed axial type of generator is used forproviding a high output. Normally, the laser gases are fed into theinterior of the laser tube through a flow control unit into which thelaser gases are introduced through a heat exchanger by means of a gasrecirculating pump. The stability of the velocity distribution of thelaser gases flowing inside the laser tube, the injection power, and theoutput beam are governed by the construction of the flow control unitand the laser tube.

Conventionally, it is known that the velocity distribution of the lasergases flowing in the laser tube is such that the velocity of the part ofthe laser gases adjacent to the wall surface is reduced, while that ofthe part of the gases in the dead center of the laser tube is increasedas a result of friction between the gases and the wall surface of thelaser tube. Accordingly, in order to make the velocity distribution ofthe laser gases in the laser tube homogeneous, conventionally turbulentflow or vortexes are produced in the laser gases. However, localizedhigh velocity flow is produced, and non-homogeneous velocitydistribution occurs, so the desired results are not attained.

SUMMARY OF THE INVENTION

An object of the present invention is to provide, with due considerationto the drawbacks of such conventional devices, a laser tube with whichit is possible to obtain homogeneous laser gas velocity.

A second object of the present invention is to provide a laser tube withimproved laser gas output beam stability.

In order to accomplish these objects in the present invention, aconfiguration has been adopted providing a plurality of gas injectionsections for injecting laser gases into the interior of the tube at aplurality of locations in the longitudinal direction of a laser tube inwhich the laser gases flow.

A rotary motion is imposed upon the laser gases flowing in the lasertube by injecting the laser gases through these gas injection sectionsin a direction tangential to the inner peripheral wall of the lasertube. The velocity of the gases close to the inner wall of the lasertube is increased, and a homogeneous velocity distribution is obtained.

In addition, the present invention is constructed so that an insulatedmember is mounted in the flow control unit. On the insulated member aremounted a plurality of disks which have a main hole and a sub-hole andwhich are assembled one by one to form a disk stack. Both the main andsub-holes of the individual disks are connected to the gas injectionsection. Because the laser tube is constructed in the form of a diskstack, by selecting a suitable number of disks in the stack, the lengthof the laser tube may be arbitrarily set so that it is possible toregulate the output of the laser.

In the present invention, a gas flow separating block is interposedbetween the flow control unit and the disk stack to divide the flow intothe main flow and the sub-flow.

Further, the individual laminated disks of the present invention areintegrally clamped together with a press member, and a blind disk whichblocks off the sub-hole and a cathode member which houses a cathode ringare interposed between the disks and the press member. This blind diskand cathode member augment the velocity of the laser gases so that thehomogeneity of the velocity distribution is improved.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects, features and advantages of the presentinvention will become more apparent from the following description of apreferred embodiment taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a front elevation of the laser generator of the presentinvention.

FIG. 2 is the plan view of FIG. 1.

FIG. 3 is an enlarged sectional drawing, viewing along the line III--IIIin FIG. 2.

FIG. 4 is a front elevation of the assembled laser tube of the presentinvention.

FIG. 5 is an enlarged sectional drawing, viewing along the line V--V inFIG. 2.

FIG. 6 is an enlarged plan view, viewing along the line VI--VI in FIG.1, showing one part in sectional view.

FIG. 7 is a sectional drawing, viewing along the line VII--VII in FIG.5.

FIG. 8 is a sectional drawing, viewing along the line VIII--VIII in FIG.5.

FIG. 9 is a sectional drawing, viewing along the line IX--IX in FIG. 5.

FIG. 10 is a sectional drawing, viewing along the line X--X in FIG. 5.

FIG. 11 is a sectional drawing, viewing along the line XI--XI in FIG. 5.

FIG. 12 is a sectional drawing, viewing along the line XII--XII in FIG.5.

FIG. 13 is a front elevation of another embodiment corresponding to FIG.8 or FIG. 9.

FIG. 14 is a sectional drawing, viewing along the line XIV--XIV in FIG.13.

FIG. 15 is a sectional drawing, viewing along the line XV--XV in FIG. 6.

FIG. 16 is a sectional drawing, viewing along the line XVI--XVI in FIG.6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now referring to FIG. 1 and FIG. 2, a laser generator 1 comprises asupport frame 3 which generally supports the body of the unit, and acover 7 which covers a discharge unit 5 and a laser oscillating sectionof the discharge unit 5. This laser oscillating section is freelyremovable from the support frame 3. The support frame 3 is framed in alongitudinal form by a plurality of lengths of angle pipe material. Aplurality of side plates 9A and 9B are provided which are erectedrespectively at the left and the right end of the support frame 3. Thecover 7 is installed on the sideplates 9A and 9B so that it covers theupper section and the front and back sections of the discharge unit 5.

As is shown in FIG. 1 and FIG. 2, a comparatively large main heatexchanger 11 is provided at the inner side of the side plate 9B erectedon the right side of the support frame 3. This main heat exchanger 11cools the laser gases which are a mixture of helium, nitrogen, andcarbon dioxide gases refluxed from the laser oscillation section insidethe discharge unit 5.

The main heat exchanger 11 is provided with a curved tube in which flowsa cooling medium, such as cooling water, and with a plurality of coolingfins.

The discharge unit 5 forms an integral unit with a flow control unit 15,a plurality of left and right laser tubes 13 which extend in the left toright direction on a common axis and with a manifold block 17 connectedto the left and right laser tubes 13. The flow control unit 15 isconnected to both ends of the left and right laser tubes 13. Flowcontrol unit 15 controls the flow volume of the laser gases to eachlaser tube 13 to carry out resonance and amplification of the excitationbeam. The flow control units 15 are connected to a plurality of supportplates 19A and 19B which are erected in the inner direction of the sideplates 9A, 9B on the support frame 3. The discharge unit 5 is installedin a removable manner through a wedge-shaped bracket 21. Specifically, aplurality of inclined channels 15G are formed on the side surfacesopposite the respective support plates 19A, 19B which support therespective flow control units 15, as shown in FIG. 5. The support plates19A, 19B and the flow control units 15 are removably connected to eachother by the wedge shaped bracket 21 engaged under pressure in theseinclined channels 15G. The support plates 19A, 19B extend in thefront-to-back direction--that is, in a direction transverse to that inwhich the laser tube 13 extends. The support plates 19A, 19B areintegrally connected by a plurality of tie rods 23.

The laser gases are fed into the laser tube 13 which is connected to themain heat exchanger 11 to cool the laser gases which are heated by theelectric discharge inside the laser tube.

A gas circulation device (not shown in the drawings) which may be, forexample, a blower, pulls in the laser gases cooled inside the main heatexchanger 11 and feeds them to the laser tube 13. This gas circulationdevice is suitably connected to the main heat exchanger 11.

A pair of connecting tubes 25A and 25B for communication, which arepositioned parallel and in close proximity to the laser tube 13, areconnected horizontally to the main heat exchanger 11. On one hand theconnecting tube 25A is connected to the flow control units 15 which areremovably supported on the support plates 19A and 19B, through aplurality of cylindrical coupling members 27A and 27B. On the otherhand, the connection tube 25B is connected to the manifold block 17.

The connecting tubes 25A and 25B are supported by a plurality of supportblocks 29 which are erected on the support frame 3.

The laser gases which are cooled by the main heat exchanger 11, as shownin FIG. 2, are fed into the respective right and left flow control units15, in the direction indicated by the arrows, through the connectingtube 25A and the cylindrical coupling member 27A and 27B. The lasergases which are fed into the left flow control unit 15 flow in thedirection indicated by the arrows into the laser tube 13 positioned onthe left side. The laser gases fed into the flow control unit 15 on theright side flow into the laser tube 13 positioned on the right side, inthe direction of the arrows. A positive and a negative electrode (notshown on the drawings) are positioned respectively at a plurality oflocations in the laser tubes 13 to produce an electric discharge in thelaser gases flowing into the laser tubes 13 positioned in the left-rightdirection. The laser gases inside the left-to-right laser tubes 15 aremade to flow together in the manifold block 17 to cool these lasergases. The laser gases, which are made to flow together in the manifoldblock 17, flow back into the main heat exchanger 11 through the otherconnecting tube 25B and are cooled. Thereafter the laser gases arerepeatedly recycled in the manner outlined.

As shown in FIG. 1 and FIG. 2, a heat exchanger 31 equipped with anair-cooling fan for cooling the inside of the laser generator 1, whichis covered by the cover 7, is provided on the side of the connectingtube 25A inside the laser generator 1. This is indicated in more detailin FIG. 3, where it is shown that the air within the cover 7 is made toflow in the direction of the arrows by means of theair-cooling-fan-equipped heat exchanger 31, cooling the inside of thelaser generator 1, as well as cooling the laser tube 13 and the supportplates 19A and 19B.

The discharge unit 5 is mounted in a removable manner on the supportframe 3 and the support plates 19A and 19B. As shown in more detail inFIG. 1 and FIG. 5, each of the tapered flanges 21 which are mountedbetween the flow control units for the discharge unit 5, and thesupporting plates 19A and 19B are mounted and removed by means of awasher 33 for wedging in and pulling out.

A channel base 35 for the discharge unit 5, as shown in FIG. 3, issecured to the support frame 3 by a plurality of bolts 37 in a manner bywhich it can be mounted or removed. The cylindrical coupling members 27Aand 27B, by which the connecting tube 25A is connected to the flowcontrol unit 15, are connected so that they can be mounted or removed bya clamp member 39 with a U-shaped cross-section, as shown in FIG. 6. Inaddition, the connecting tube 25B is connected to the manifold block 17,in a manner allowing mounting or removals, with a pyrex joint member 41,as shown in FIG. 2.

Accordingly, when removing the discharge unit 5 from the support frame3, first the tapered flange 21 which is mounted between the supportplates 19A, 19B, and the flow control units 15 is removed through themedium of the washer 33 for wedging in and pulling out. Next, thecylindrical coupling members 27A and 27B, by which the flow controlunits 15 and the connecting tube 25A are connected, are removed byunclamping the clamp member 39. The pyrex joint member 41, which joinsthe connecting tube 25B and the manifold block 17, is then removed.Finally, the channel base 35 is removed from the support frame 3 byloosening the bolts 37. As a result, as shown in FIG. 4, the dischargeunit 5 can be removed from the support frame 3 of the laser generator 1.

As shown in FIG. 4, the discharge unit 5 comprises the channel base 35,the flow control units 15, the manifold block 17, the laser tube 13, aplurality of laser tube supporters 43 which support the laser tube 13,and a plurality of hangers 45 from which the discharge unit 5 issuspended. The control units 15 are mounted on both ends of the channelbase 35. The manifold block 17 is mounted at almost dead center of thechannel base 35. The laser tube 13 is connected between the flow controlunits 15 and the manifold block 17. The hangers 45 are erected on thechannel base 35 close to the inward faces of the flow control units 15through a plurality of hanger seats 47. These hangers 45 are used whenthe discharge unit 5 is being installed on or removed from the lasergenerator 1, and the removal is carried out by suspending the dischargeunit 5 from the hangers 45.

The laser tube supporters 43 are erected on the channel base 35 at bothsides of the manifold block 17 to support the laser tube 13. As shown inmore detail in FIG. 3, a height adjustment liner 49 is provided on thechannel base 35. The height adjustment liner 49 comprises an uppertapered liner 49A and a lower tapered liner 49B. A bolt 51 is insertedthrough a hole formed in the upper tapered liner 49A and the lowertapered liner 49B. The upper tapered liner 49A is made to slide againstthe lower tapered liner 49B in the left-right direction in FIG. 3 byrotating the bolt 51 in the clockwise or counterclockwise directions.Accordingly, the height adjustment is performed by causing the taperedface of the lower tapered liner to slide against the tapered face of theupper tapered liner.

The laser tube 13 is mounted on the height adjustment liner 49, and issupported by the laser tube supporter 43. The laser tube supporter 43comprises a pair of side surface clamp blocks 43A and an upper surfaceclamp block 43B. An adjustment device 53, which clamps the laser tube 13with the side surface clamp blocks 43A and the upper surface clamp block43B in the left-right and up-down directions in FIG. 3, is provided onthe upper surface clamp block 43B. An adjustment member 55 which adjuststhe clamping of the upper surface clamp block 43B and the right sidesurface clamp block 43A is mounted on the upper surface clamp block 43B.The tip of the adjustment member 55 points in the upper direction andhas a protruding section 55A. The protruding section 55A penetratinglyprotrudes through an orifice 57 formed in the upper section of the rightside of the side surface clamp block 43A and touches the outer sidesurface of the right side surface clamp block 43A.

The adjustment member 55 is hollow. Furthermore, a support block 61 isprovided in which a slot 59 is formed in the upper surface on the rightside. An adjustment member 63, which adjusts the left side surface clampblock 43A, is mounted on the hollow section of the support block 61. Aslot 65 is formed on the right side section of the adjustment member 63.The support block 61 and the adjustment member 63 are mounted in theslot 65 by a pin 67 installed on the right side section of the supportblock 61. A tapered section 63A is provided on the left side section ofthe, adjustment member 63 and it penetrates into a hole formed in theupper section of the left side surface clamp block 43A. Further, the topinner surface of a hole formed in the upper section of the left sidesurface clamp block 43A is tapered to slide along the tapered surface ofthe tapered section 63A. A screw 69 is installed in the inside of a holeformed at the common position of the support block 61 and the adjustmentmember 63. A knob 71 is mounted on the upper end of this screw 69.

Accordingly, rotating this knob 71 in either the clockwise or thecounterclockwise directions causes the screw 69 to rotate. When thescrew 69 is tightened, the left end of the adjustment member 63 slidesin the upper direction in FIG. 3, and the tapered section 63A of theadjustment member 63 touches the upper surface tapered section of thehole formed in the left side surface clamp block 43A, and secures theleft side surface clamp block 43A. In addition to securing the left sidesurface clamp block 43A, the tip of the screw 69 also applies pressureagainst the adjustment member 55. If the screw 69 is tightened further,the protruding section 55A at the tip of the adjustment member 55 ispulled by the component of the force in the horizontal direction actingon the tapered section 63A of the adjustment member 63. As a result, theprotruding section 55A presses against the outside surface of the rightside surface clamp block 43A so that force is applied to the inside toclamp the laser tube 13 in place.

Then, through the action of the force in the direction of the arrow F asindicated in FIG. 3, the laser tubes 13 are supported in all fourdirections. At that time, a notch 73 provided in the lower direction ofthe left and right side surface clamp blocks 43A plays the role ofneutralizing an extreme force F applied to the left and right of theside surface clamp blocks 43A, or a shock. As discussed, the laser tubesupporter 43 comprising the side surface clamp blocks 43A and the uppersurface clamp block 43B protect the laser tubes 13 during shipment.

As is clearly seen in FIG. 4, a preionization resistor holder 75 whichcan be an insulated unit which houses a high resistance resistor 77 isprovided on the upper section of the manifold block 17. An insulatedacrylic cover 79 is fitted on its upper section. One end of the highresistance resistor 77 is connected to the channel base 35 by a highvoltage cable 81, while the other end is connected to the manifold block17 with the high voltage cable 81. In this way, when a high voltage isapplied to a cathode ring 83 housed in the laser tube 13 a glowdischarge is produced between the cathode ring 83 and the manifold block17, and the value of the current carries out a preionization of severalmilliamperes.

As has already been explained with reference to FIG. 4, the laser tubes13 are connected between the flow control units 15 and the manifoldblock 17. Next, the detailed configuration of the laser tubes 13 willnow be explained with reference to FIG. 5 and FIGS. 7 to 14. The leftand right laser tubes 13 are either identical or mirror images.Therefore the explanation will be made with reference to the left lasertube 13 shown in FIG. 5 and the explanation of the right laser tube 13will be omitted.

As shown in FIG. 5, a plurality of, for example, four insulated studs 85are mounted on one side surface of the flow control unit 15, and thesestuds 85 act to combine a gas flow separator block 87, a plurality offirst stage disks 89, a plurality of second stage disks 91, a blind disk93, a cathode plate 95, and a press flange 97 in that order, into anintegral laminated structure.

As shown in FIG. 5 and FIG. 7, the gas flow separator block 87 is madeof ceramic. A main hole 99 is formed in the shaft center section, and acylindrical protruding section 101 which protrudes toward the flowcontrol unit 15 is provided at the outer wall of the main hole 99. Aplurality of, for example, four sub-holes 103 are formed around thecircumference of the base of the protruding section 101. In addition, aplurality of studbolt holes 105 are provided to be penetrated by theinsulated studs 85 at, for example, the four corners. Accordingly, thegas flow separator block 87 can be mounted on one side surface by meansof the plurality of insulated studs 85. The laser gases flow from thecontrol unit 15 through the main hole 99 and the sub-holes 103.

As shown in FIG. 5 and FIG. 8, the first stage disk 89 is made ofceramic in the same way as the gas flow separator block 87, and, inaddition, four studbolt holes 105 are formed, for example, in the fourcorners. Also the main hole 99 and the sub-holes 103 are formed on thefirst stage disk 89, in the same way and of the same diameter as on thegas separator block 87. A gas injection section in the form of a gasinjection channel 107 which injects the gases in the tangentialdirection is formed between the outer circumference of the one main hole99 and the four sub-holes 103, and is connected to them. Further, sothat the conductance in a second stage disk 91, which will be laterdiscussed, will not become small, the diameter of the sub-hole 103 ofthe first stage disk is made larger than the diameter of the sub-hole103 of the second stage disk 91.

Accordingly, a plurality of insulated studs 85 are inserted from thestud holes 105 into the first stage disks 89, making a plurality oflaminations with the gas flow separating block 87. The laser gases flowfrom the main hole 99 of the flow separator block 87 into the main hole99 of the laminated first stage disks 89. Also, the laser gases flowfrom the sub-hole 103 of the flow separator block 87 into the sub-holes103 of the laminated first stage disks 89, and are injected from the gasinjection channels 107 in the tangential direction of the main hole 99,and the velocity of the gases close to the inner wall of the laser tubeis increased, so that a homogeneous velocity distribution is obtained.

As shown in FIG. 5 and FIG. 9, the second stage disks 91 are constructedalmost the same as the first stage disks 89 so a detailed explanation ofthe construction will be omitted. However, the laminated second stagedisks 91 differ from the first stage disks 89 inasmuch as the diameterof the sub-hole 103 is smaller than that of the sub-hole 103 of thefirst stage disks 89 so that the cross-sectional area is smaller, sothat the velocity of the laser gases is homogeneously augmented.

Now referring to FIG. 5 and FIG. 10, a blind disk 93 is made of ceramicand the studbolt holes 105 which are penetrated by the insulated studs85 are formed in the four corners. The main holes 99 are formed in theshaft center section and the sub-holes are blocked off.

Now referring to FIG. 5 and FIG. 11, the cathode plate 95 is made ofstainless steel, and a nickel cathode ring 83 is pressed into the innerdiameter section. A high voltage is applied to the cathode ring 83. Thestudbolt holes 105 for inserting the insulated studs 85 are formed inthe four corners in the same way as for the other disks discussed up tothis point. The cathode plate 95 is interposed between the blind disk 93and the press flange 97 forming a laminated unit.

Now referring to FIG. 5 and FIG. 12, the press flange 97 acts a guidefor the four insulated studs 85, and by tightening the studs 85, anintegrated laminated laser tube is formed by pressing these disk typestogether. On this press flange 97, a cylindrical protruding section isformed which is inserted in the holes formed in the manifold block 17.

Now referring to FIG. 13 and FIG. 14, a heat sink 109 is fastened, forexample, by the use of epoxy adhesive, to the outer circumferentialsection of the first stage disk 89 and the second stage disk 91,actively cooling the disk itself for improved cooling. With the aboveconstruction, the length of the laser tube can be arbitrarily adjustedby setting a suitable number of laminations for the first stage disks 89and the second stage disks 91.

An explanation of the specific construction of the left and right flowcontrol units 15 mounted on both ends of the discharge base 35 of thedischarge unit 5, will be given here. However, because they areidentical or mirror images, the explanation of the right flow controlunit 15 is omitted.

Now referring to FIG. 5 and FIG. 6, the laser gases in the connectingtube 25A are fed through the coupling member 27A in the direction of thearrow on the flow control unit 15. A ceramic cylindrical flow controlvalve 111 and an anode ring 113 are provided, opposed to the axialdirection of the laser tube 13, in the flow control unit 15. Theprotruding portion 101 of the gas flow separation block 87 of the lasertube 13 is inserted almost as far as the center of the flow controlvalve 111 provided inside the flow control unit 15. An annular space 115is formed between the flow control valve 111 and the anode ring 113, andthe laser gases are injected in the direction shown by the arrow fromthe annular space 115 to the main hole 99 side of the laser tube 13. Theflow control valve 111, fitting into the flow control unit 15, issuitably mounted on a support section formed almost at the center of theflow control unit 15. A first gas chamber 117 and a second gas chamber119, which are suitably connected to the connecting tube 25A, are formedon both sides of this support section. The flow control valve 111 andthe anode ring 113 are positioned in opposition, in the first gaschamber 117. The protruding section 101 of the gas flow separation block87 is extendingly inserted into the flow control valve 111. Accordingly,the laser gases are fed through the connection tube 25A and thecylindrical coupling member 27A into the first gas chamber 117. Thelaser gases which are fed into the first gas chamber 117 flow uniformlyin the direction of the arrows from all around the annular space 115formed between the flow control valve 111 and the anode ring 113 intothe main hole 99 of the laser tube 13.

The laser gases from the flow control unit do not flow into the lasertube 13 at right angles, as in conventional tubes, but flow from allaround the annular space 115 as uniformly as possible into the main hole99 to the inside of the laser tube 13. For this reason, the laser beamoutput mode is improved by the reduction of fluctuation of the lasergases, and when this equipment is used in a laser process, the degree ofroughness of the surface of the workpiece is much better than obtainedconventionally.

Furthermore, the second gas chamber 119 is suitably connected to thesub-holes 103 of the laser tube 13. Accordingly, the laser gases fedthrough the connection tube 25a and the cylindrical coupling member 27Aflow into the second gas chamber, and the laser gases which flow intothe second gas chamber 119 are caused to flow through the sub-holes 103of the laser tube 13 into the main hole 99.

In FIG. 5 and FIG. 6, and as shown in FIG. 15 and FIG. 16, a sub-flowcontrol valve 121 which controls the volume of flow into the sub-holes103 in the flow control unit 15, and a main flow control shaft 123 whichcontrols the previously explained flow control valve 111, are provided.In addition, a dust trap cap 125 for use as a dust trap, a rod 127 forchecking the degree of opening of the sub-control valve 121, a window129 for checking the degree of opening of the flow control valve 111,and a power supply stud 131 for providing power, are provided in theflow control unit 15.

The control of the flow of laser gases to the sub-hole 103 is carriedout by adjusting a cylindrical sub-flow control valve 121 provided witha plurality of holes 121H which adjust the sub-holes 103 by throttling.More specifically, as is clearly indicated in FIG. 15, an operating rod133, which provides the rotary action of the sub-flow control valve 121on one side surface of the flow control unit 15, is screwed onto adisk-shaped support block 135. The tip section 133E of the operating rod133 contacts an adjustment block 137 which is mounted in the sub-flowcontrol valve 121. On the other side surface, which is in the oppositedirection of the flow control unit 15 which removably supports theoperating rod 133, the rod 127, which is used to check the degree ofopening of the sub-flow control valve 121, is removably supported by asupport block 139 so that it may freely enter and exit. This valveopening check rod 127 is inserted into a hole formed in the flow controlunit 15. Its tip section 127E contacts an adjustment block 141 which ismounted on the subflow control valve 121. A spring 143 is installedwithin a hole formed in the flow control unit 15, and is usuallyenergized toward the tip section 127E of the valve opening check rod127.

Then by rotating a knob 145 provided on the operating rod 133 in theclockwise or counterclockwise direction, the tip section 133E of theoperating rod 133 applies pressure against the adjustment block 137,and, in addition, rotary action is applied to the adjustment block 137and the sub-flow control valve 121 rotates. The cross-sectional area ofa throughhole into the sub-hole 103 is continuously throttled throughthe rotation of the sub-control valve 121, and the volume of flow of thelaser gases passing through the sub-hole 103 is adjusted. With therotation of the sub-flow control valve 121, the tip section 127E of thevalve opening check rod 127 resists the energy of the spring 143.Pressure is applied to the adjustment block 141 and the valve openingcheck rod 127 moves in the outward direction. By viewing this action theadjustment of the sub-flow control can be checked.

A protective cap 147 is screwed into the outer surface of thedisk-shaped support block 135 to prevent unauthorized manipulation ofthe knob 145 provided on the operating rod 133, after the adjustment ofthe sub-flow control.

The volume of flow of the laser gases to the main hole 99 is controlledby moving the main control shaft 123 in the axial direction of the flowcontrol valve 111. More specifically, as is clearly indicated in FIG.16, the main flow control shaft 123 on one side surface of the flowcontrol unit 15 is removably supported on the disk-shaped support block149. The main flow control shaft 123 extends into a hole formed in thesupport block 149, facing in the rear direction of the part removablysupported on the flow control unit 15. A cam 151 is mounted on one endof the main flow control shaft 123. The cam 151 is positioned in achannel 153 formed in the flow control valve 111, so that the flowcontrol valve 111 can be moved forward and backward in the axialdirection. Accordingly, by rotating a knob 155 on the other end of themain flow control shaft 123 in the clockwise or counterclockwisedirection, the tip of the cam 151 moves back and forth in the axialdirection so the space 115 is adjusted, thus adjusting the volume offlow of the laser gases to the main hole 99. Also, a cap 157, whichscrews onto the disk-shaped support block 149, completely encloses theknob 155 and prevents any unauthorized handling.

In order to fill the dust trap function, the dust trap 125 is installedon the flow control unit 15. More specifically, as clearly indicated inFIG. 16, the dust trap cap 125 is mounted on the side surface of theflow control unit 15 opposite from the cylindrical coupling member 27A.A silicone grease 159 is applied to the inside surface of the dust trapcap 125 to adsorb dust. Accordingly, because the laser gas flow from thecoupling unit 27A to the flow control unit 15 is deflected 90 degrees,the fine particles of dust are removed through the difference in inertiabetween the gases and the fine particles of dust. These fine particlestravel straight ahead from inertia and are adsorbed on the siliconegrease on the inside of the dust cap 125, while the lighter laser gaseshead upward to be injected. As a result, delicate parts such as theoutput mirror are protected from dust.

The main flow control opening check window 129 is installed on the topsurface of the flow control unit 15. More specifically, as clearlyindicated in FIG. 5 and FIG. 6, the check window 129, made oftransparent acrylic, is installed on the upper surface of the flowcontrol unit 15 for checking the degree of opening of the control unit.An orifice 161 is formed in one section of the flow control unit 15,opening into the first gas chamber 117 formed in the flow control unit15. The inside of the flow control unit 15 can be observed through thecheck window 129.

Accordingly, the space 115 between the anode ring 113 and the flowcontrol valve 111 can be observed and checked through the check window129, so that the adjustment of the flow control valve 111 by means ofthe main flow control shaft 123 can be easily checked.

The power supply stud 131 is installed on the flow control unit 15 tosupply power to the anode ring 113. The power supply stud 131 extendsinto an orifice formed in the flow control unit 15 and its tip isstopped at the anode ring 113 by a stopper fitting. The flow controlunit 15 itself is electrically insulated so that power is fed to theanode ring 113 by the power supply stud 131.

Now referring to FIG. 1 and FIG. 2, an output mirror assembly forresonant amplification of the excited beam which is excited by theelectrical discharge inside the laser tube 13 is supported by thesupport plate 19A. A rear mirror assembly is supported by the supportplate 19B. More specifically, as clearly indicated in FIG. 5 and FIG. 6,a stepped hole 163 is formed in the axial direction opposed to the mainhole 99 of the laser tube 13, matching with the inside of the supportplate 19A. A mirror holder 165 is mounted in the stepped hole 163, andthe output mirror assembly 167 is removably supported in the mirrorholder 165.

The output mirror assembly 167 comprises an inner ring member 171 whichsupports an output mirror 169, an outer ring member 173, and a fixedring member 175. An annular cooling chamber 177 is formed between theinner and outer ring members 171 and 173. A cooling medium, such aswater, flows freely through this annular cooling chamber 177 to cool theoutput mirror 169. One part of the mirror holder 165 is inset andsupported in a freely rotating manner through a ball joint or similardevice so that the mirror holder 165 can swing in the forward andbackward direction for adjustment of its angle. Now referring again toFIG. 5 and FIG. 6, a pin 179 is inserted into a hole formed in thesupport plate 19A and the mirror holder 165, and is adjusted by means ofan adjustment bolt 181. The angled tip of the pin 179, as shown in FIG.6, contacts a wedge 185 formed in one section of the shaft 183 which isfitted into the support plate 19A. A screwed member, suitably connectedto one end surface of the shaft 183, mates through a spline with theoutput shaft of a control motor 187, which may be a servomotor.

When the control motor 187 is driven, the shaft 183 moves in the upwardand downward direction in FIG. 6. The pin 179 is caused to move upwardand downward in the axial direction by the movement of the shaft 183.The mirror holder 165 is made to swing by the forward and backwardmovement of the pin 179, and the angle of the output mirror 169 is thusadjusted.

The construction of the rear mirror assembly is almost the same as thatof the output mirror assembly, so a detailed description is omittedhere.

As may be understood from the above explanation of the embodiment, inthe present invention, because gas injection sections which injects thelaser gases into the laser tube are provided in a plurality of positionsin the longitudinal direction of a laser tube in which laser gases flowin the longitudinal direction, the velocity of the laser gases close tothe inner wall of the laser tube is increased so that a homogeneousvelocity distribution is obtained. Because the direction of the gasinjection at the gas injection section is tangential to the innerperipheral wall of the laser tube, the velocity of the laser gases isincreased, and as a result, a homogeneous laser gas velocitydistribution is obtained.

In the present invention, individual disks with both main holes andsub-holes are laminated, and the main holes and sub-holes are connectedat the injection sections. In addition, because the injection of thelaser gases through the injection sections from the sub-holes is in thetangential direction in the main holes, the velocity of the laser gasesclose to the inner wall of the main hole is more efficiently increased,and a homogeneous laser gas velocity distribution is obtained. Thehomogeneity of the velocity distribution of the laser gases at both theupstream walls and the downstream walls is kept uniform, so that thestability of the beam and the power input are improved in comparisonwith conventional equipment.

Although only preferred embodiments are specifically illustrated anddescribed herein, it will be appreciated that many modifications andvariations of the present invention are possible in light of the aboveteachings and within the purview of the appended claims withoutdeparting from the spirit and intended scope of the invention.

What is claimed is:
 1. A laser tube for a laser generator having acontrol unit for controlling the flow volume of a laser gas which flowsin said laser tube, said laser tube comprising:a plurality of diskslaminated together and connected at one end of said laminated pluralityof disks with said control unit; each of said disks having a main holefor the passage of laser gas therethrough and a sub-hole for the passageof laser gas therethrough, wherein the main hole and sub-hole of eachindividual disk are connected for fluid communication therebetween at agas injection section; wherein said plurality of laminated diskscomprises a first disk which has a sub-hole with a predeterminedcross-sectional area and a second disk which has a sub-hole with across-sectional area which is smaller than the cross-sectional area ofthe sub-hole of said first disk, said second disk being positioned awayfrom said flow control unit with respect to said first disk.
 2. Thelaser tube for a laser generator of claim 6 wherein the laser gas isinjected into the main hole from the sub-hole of each individual disk ofsaid plurality of laminated disks through the gas injection section ofeach individual disk in a direction tangential to the periphery of themain hole of each individual disk.
 3. The laser tube for a lasergenerator of claim 6 wherein a gas flow separation block having a mainhole and sub-hole for separating the flow into a main flow for the flowof gas into the main hole of said plurality of laminated disks and asub-flow for the flow of gas into the sub-hole of said plurality oflaminated disks is interposed between said flow control unit and saidplurality of laminated disks.
 4. A laser tube for a laser generatorhaving a control unit for controlling the flow volume of a laser gaswhich flows in said laser tube, said laser tube comprising:a pluralityof disks laminated together and connected at one end of said pluralityof laminated disks with said control unit; each of said disks having amain hole for the passage of laser gas therethrough and a sub-hole forthe passage of laser gas therethrough, wherein the main hole andsub-hole of each individual disk are connected for fluid communicationtherebetween at a gas injection section; wherein the individuallaminated disks are clamped together with a press member to form aintegral unit.
 5. The laser tube for a laser generator of claim 7wherein a blind disk, in which no sub-hole is formed, is interposedbetween the plurality of laminated disks and the press member.
 6. Thelaser tube for a laser generator of claim 8 wherein a cathode memberwhich includes a cathode ring is interposed between the blind disk andthe press member.
 7. A laser tube for a laser generator comprising:aflow control unit for controlling the flow of laser gas in the lasertube in the longitudinal direction; a primary opening in the laser tubefor the passage therethrough of laser gas, said primary opening beingconnected with said fluid control unit at one end of said primaryopening; means for injecting laser gas into said primary opening in adirection normal to the longitudinal direction of the laser tube at aplurality of longitudinal positions of the laser tube; a plurality ofdisks stacked and joined together to form an integral unit, each of saiddisks having a main hole therethrough, each of said main holes beingaligned with one another so as to form said primary opening for thepassage of laser gas, wherein said means for injecting laser gas intothe primary opening comprises a sub-hole in each of said disks, saidsub-holes being aligned with one another and in communication with thefluid control unit, and a gas injection channel connecting the sub-holeof each disk with the main hole of the respective disk, whereby lasergas flows from said sub-hole through said gas injection channel intosaid main hole; wherein said plurality of disks further comprises afirst disk having a sub-hole of predetermined cross-sectional area and asecond disk having a sub-hole with a cross-sectional area less than thatof the sub-hole of said first disk, and wherein said first disk and saidsecond disk are stacked so that said first disk is closer to the fluidcontrol unit than said second disk.
 8. The laser tube for a lasergenerator of claim 7 further comprising a plurality of sub-holes in eachof said disks and a gas injection channel connecting each of saidsub-holes with the main hole on each of the respective disks.
 9. Thelaser tube for a laser generator of claim 7 further comprising meansinterposed between the plurality of stacked disks and the fluid controlunit for separating the flow of laser gas entering the laser tube into amain flow and a sub-flow and diverting said main flow into said primaryopening and said sub-flow into said sub-holes.
 10. The laser tube for alaser generator of claim 9 wherein said means for separating anddiverting the flow of laser gas entering the laser tube is a gas flowseparation block having a main hole in communication with the fluidcontrol unit, a cylindrical protruding section surrounding the main holeand extending toward the flow control unit, and a sub-hole incommunication with the fluid control unit.
 11. The laser tube for alaser generator of claim 9 further comprising means for controlling themain flow of laser gas entering the primary opening.
 12. The laser tubefor a laser generator of claim 9 further comprising means forcontrolling the sub-flow of laser gas into the sub-holes.
 13. A lasertube for a laser generator comprising:a flow control unit forcontrolling the flow of laser gas in the laser tube in the longitudinaldirection; a primary opening in the laser tube for the passagetherethrough of laser gas, said primary opening being connected withsaid fluid control unit at one end of said primary opening; means forinjecting laser gas into said primary opening in a direction normal tothe longitudinal direction of the laser tube at a plurality oflongitudinal positions of the laser tube; a plurality of disks stackedand joined together to form an integral unit, each of said disks havinga main hole therethrough, each of said main holes being aligned with oneanother so as to form said primary opening for the passage of laser gas,wherein said means for injecting laser gas into the primary openingcomprises a sub-hole in each of said disks, said sub-holes being alignedwith one another and in communication with the fluid control unit, and agas injection channel connecting the sub-hole of each disk with the mainhole of the respective disk, whereby laser gas flows from said sub-holethrough said gas injection channel into said main hole; furthercomprising a press means for clamping said plurality of disks togetheras a unit, said press means being disposed at the end of said laser tubeopposite said fluid control unit.
 14. The laser tube for a lasergenerator of claim 13 wherein said plurality of disks further comprisesa blind disk having means for blocking the flow of laser gas through thesub-holes of said plurality of disks and said blind disk is interposedbetween said plurality of disks and said press means.
 15. The laser tubefor a laser generator of claim 18 wherein a cathode member whichincludes a cathode ring is interposed between said blind disk and saidpress means.